(1) Technical Field
The present invention relates to an image forming apparatus and an image forming method.
(2) Related Art
In recording apparatus hitherto used for forming color images in accordance with an electrophotographic system, fundamental three primary colors are developed according to information on their respective images and these toner images are superposed one by one, and thereby color images are obtained. As to a specific apparatus configuration, there is known the so-called 4-cycle machine in which development of latent images formed on one photoconductor drum according to a method of image formation is performed for each color and transfer of developed color images onto a transfer member is repeated for each color, and thereby color images are obtained; or a tandem machine in which a photoconductor drum and a developing device are installed for an image forming unit of each color and toner images are continuously transferred onto a transfer member one after another by travel of the transfer member, and thereby color images are obtained.
At least one thing these machines have in common is that plural developing devices are provided for colors to which they are allocated, respectively. Therefore, usual color image formation requires 4 developing devices for three primary colors plus black color, and a tandem machine further requires not only 4 photoconductor drums responding to 4 developing devices but also an unit for harmonizing the synchronization among these 4 image forming units; as a result, upsizing of the apparatus and a cost increase become unavoidable.